But then something changed and by the late nineteen nineties construction tradition had been refashioned around contradictory practice: brilliant, game-changing bridges, museums, libraries or dams were built against a backdrop of squads of nondescript endeavours. A good deal of disorderly construction went on. With the advent of an unprecedented economic crisis toward the end of the two thousands, the expectations generated around the pursuit of excellence were overshadowed by the evidence of excess. Perplexity mounted around certain purposeless works, the genesis of which cannot be readily explained. Unused motorways and airports, empty museums and libraries hit the headlines.

The volume of construction in recent decades, along with the magnitude of the crisis, are powerful reasons for reflection on what was built and what happened. This book discusses three notions in that regard: review of investment from a technical and socioeconomic perspective; description of the territorial changes inferred by those facts and figures and the respective works processes and typologies; and the opinion of those who led the country's construction for decades. An after-note is included on what those leaders are thinking and doing now, primarily in connection with works outside Spain.

The book's various chapters:
- describe the economic scenarios that favoured the enormous change taking place in recent years and the trends discernible from that review;
- analyse the territorial significance of built structures by type of work: mobility, water and energy and urban systems, with a section devoted to the coast;
- introduce a series of considerations around the construction product by the actors involved: architects, civil engineers and planners, with a brief illustrated text succinctly describing a small sample of those actors' accomplishments abroad, including some of the projects and works underway.
The book concludes with references to works undertaken by ACS, although given the breadth of the subject, it covers no more than a fraction of the total.

The title itself, 'Outstanding Spanish Roofs', carries that inference, suggesting not only the size but a presence that clearly looms above any other component. The subjects of the book's chapters include:

- a reflection on the significance of roofs, the origin of their meaning and their lightness, a notion addressed in earlier publications in this series on building structures and footbridges and invoked here (for the issue consistently arises when bending stress is the predominant force acting on a structure), along with its limits in connection with two extreme structures: geodesic domes and the tensegrity system;

- the origin of roofs per se, a modern expression of building endeavour clearly associated with iron and its pairing with glass;

- the variety of materials and types stemming from the maturity attained in outstanding roofs: the acme of concrete, thin concrete shells and welded wire mesh reinforcement;

- major Spanish works, analysed and illustrated by their authors.

This publication also affords the opportunity to review a sizeable number of distinctive buildings, tall towers and splendid roofs too recently erected in Spain to have been included in the book Structures for Outstanding Spanish Buildings released n 2008. Most of these reviews were also written and illustrated by the actors involved.

The problems that chronically beset railways are addressed against that backdrop. Rather than 'repairing' or 'reworking' traditional trouble spots, the idea was to induce a game change, raising service quality to the performance levels characteristic of other European countries. The Madrid-Seville high-speed line (known locally as the 'AVE') is distinctly different from traditional railways. Designed to user comfort and convenience and marketed as a new experience inspired by air travel, its initial success prompted demands from other Spanish cities and regions for similar service, making the 'AVE' a must-have in all territorial aspirations.

In parallel and less visible but of enormous importance was the increasing emphasis on commuter services in large cities, closely related to the new philosophy of mobility. Newly democratic municipal governments channelled transport infrastructure investment toward railways as the sole solution to routinely over-congested urban access roads.

The book addresses:
- the conceptual and aesthetic meanings of speed in connection with travel in general and railway travel in particular;
- the 'AVE's' territorial expansion in Spain, with a discussion of the episodes that informed decisions on its layout;
- the implications of high-speed railway technology, operation and aesthetics; - the major works;
- bridges and stations, with descriptions and analyses entrusted to their authors.
It ends with a synopsis of ACS's most representative works on 'AVE' lines.

Even when limited, as in this book, to a single decade (2000-2009) and a specific geography, Spain, the study of footbridges is a daunting task due to the huge number and wide variety of such structures.

In footbridges, perhaps more than in their road/railway counterparts, site-related boundary conditions, mirrored in the design, constitute one of the primary areas of interest. That is intensified by the scant consequence of structural issues, which can normally be solved with no need for special measures in terms of materials or layout both in the resistant as in construction procedures. As a result, footbridges are described here from the classical perspective of structural types. The significance of footbridges is also studied, along with the variables characteristic of their design: scale, ease of adaptation to the context, the importance of access, the allure of elegant elevations and the expressive potential of lightness.

The 300-some footbridges reviewed in this book are described and illustrated by the designers themselves, rather than on the grounds of the editor's own criteria and photographs. No-one is better placed to enhance comprehension of a work than its author, particularly when construction is too recent for a store of critical analysis to have amassed.

It focuses on buildings where the structural role is neither predominant nor passive, but imperative as a component of the whole in which its expression is integrated. Comprehension of the depth and characteristics of the relationship between structure and architecture, the part and the whole, is contingent upon understanding structural behaviour.

The review is limited to outstanding buildings of a certain size in which the structure bears specific weight in the overall conception, built in Spain between 1994 and 2008.

The book discusses:

- the significance of structure today, with a reflection on the reasons for and implications of change in the approach to understanding structure;

- the skeleton, less literally than in terms of its status as structural embryo ever since stone bearing walls ceased to be a construction imperative;

- towers as buildings in which height prevails over all other dimensions, calling for a particular type of structures specifically designed to tackle horizontal axis bending- and vibration-related problems;

- skin and openings, denomination chosen in light of the dissociation between façade and usable area and, concomitantly, the vast open plan storeys that require structures distinctly different from those of earlier endeavours.

Examples drawn from other countries are used to establish concepts and typological precedents, with special reference to buildings with structural solutions that serve as benchmarks. A few Spanish works prior to 1990 are also included as precedents for the in-country development of structures for large buildings.

Most of the book consists in texts, drawings and photographs furnished by the architects and engineers who designed these works and their structures. In addition to the data and illustrations, many of the reviews authored by these professionals include valuable remarks and critical reflections that enrich its content.

I ends with ACS's intervention in such structural works.

These ideas are formulated in Chapter 2, which discusses bridges as notion and the role of type and site in their design process. The profiles of both the last stone bridges erected and those made of iron and concrete exhibit elevations where a Roman compositional legacy is perfectly recognisable. After 1950, prestressed concrete continuous beam bridges prevailed worldwide, although in Spain the earliest such structures only began to appear in the late nineteen sixties. This chapter concludes with a discussion of character as the key to studying form, which transcends the merely descriptive to embrace the expressive whole of bridges and explain the resources used to showcase their significance.

The following three chapters revolve around type. Chapter 3 refers to arch bridges, Chapter 4 to beam bridges and portal frame and Chapter 5 to suspension and cable-stayed bridges. The sixth chapter describes two archetypical bridge types, exemplified by the Alcántara and Mérida Bridges, along with others that feature specific conditions: bridges over reservoirs or border bridges. Chapter 7 addresses urban bridges, classified under three major headings: in cities with steeply banked rivers, in coastal cities with generally low-lying shores and in mid-stream cities with variable situations. A case study of Madrid describes how its prevalence as the capital city is portrayed in bridges of much greater entity than warranted by the obstacle posed by the River Manzanares.

The book concludes with a review of the most significant bridges built by ACS.